Update GA4Exception to fit PHP7.0

Author: Alex Westergaard

src/GA4Exception.php

@@ -4,7 +4,7 @@
 
 class GA4Exception extends \Exception
 {
-    public function __construct(string $message = "", ?\Throwable $previous = null)
+    public function __construct(string $message = "", $previous = null)
     {
         parent::__construct($message, 0, $previous);
     }

test/AnalyticsTest.php

@@ -1,9 +1,9 @@
 <?php
 
 use AlexWestergaard\PhpGa4\Analytics;
-use AlexWestergaard\PhpGa4\GA4Exception;
 use AlexWestergaard\PhpGa4\Item;
 use AlexWestergaard\PhpGa4\UserProperty;
+use AlexWestergaard\PhpGa4\GA4Exception;
 
 class AnalyticsTest extends \PHPUnit\Framework\TestCase
 {
@@ -60,7 +60,6 @@ public function testExceptionIfTimeOlderThanOffsetLimit()
 
         try {
             $this->analytics->setTimestamp(strtotime('-1 week'));
-            $this->assertTrue(false, "Did not receive correct Exception");
         } catch (GA4Exception $e) {
             $this->assertTrue(true);
         } catch (Exception $e) {